Dogfighting cases are way up in Philadelphia since Michael Vick signed with the Eagles. Is it a citywide crackdown, or did Vick bring a terrible fad north with him?

According to the SPCA, the number of animal fighting investigations in Philadelphia rose from 245 in 2008 to 903 in 2009, with an explosion after Vick's August signing. We see three possible explanations.

The first and most likely, and the one we hope is true, is that people are just more aware of the practice. More people are reporting it, and law enforcement is specifically targeting it in the wake of national discussions. That's the Humane Society's theory.

Nationally, states and law enforcement agencies have been cracking down on dogfighting since the Vick case, said John Goodwin, manager of animal fighting issues for the Humane Society of the United States. In the 2008 and 2009 legislative sessions, he said, 27 state laws were passed cracking down on animal fighting.

He also said the number of law enforcement actions related to animal fighting roughly doubled from pre-Vick in 2006 to after his conviction in 2008 - which he attributed to greater awareness and motivation on the part of law enforcement agencies, not an increase in dogfighting.

But the SPCA isn't so sure. In Philadelphia, the increase in vigilant citizens reporting dogfighting doesn't explain the threefold increase in investigations in a single year.

Reporting is up about 25 percent from previous years, [SPCA's Pennsylvania law enforcement director George] Bengal said, and the SPCA has devoted more officers to investigate animal fighting. But he said there also has been an increase in actual dogfighting.

This is a fad out here now," he said, adding that it's hard to break down exactly how many of the cases are new operations.

That's been the talking point for area animal rights groups ever since Vick signed.

By hiring Michael Vick, the Eagles brought clear attention to a very awful thing that's done to animals," said Tom Hickey Sr., founder of the Pennsylvania advocacy group DogPAC. "But also by hiring him, they also said it's OK to do this kind of stuff."

We're not sure what's really happening here, but we're not willing to rule out a third, darker possibility. A sinister one-man crime spree, with Vick running dogfighting operations out of hundreds of homes in the Philadelphia area.